1. Field of the Invention
The present invention relates to a cut valve which is installed on a fuel tank of an automobile or the like and is adapted to shut off a vent passage between the interior of the fuel tank and the outside when the fuel level in the fuel tank has risen, so as to prevent leakage to the outside.
2. Description of the Related Art
A fuel tank of an automobile is provided with a fuel vapor pipe for discharging fuel vapor to a canister through a cut valve and a check valve when the internal pressure has exceeded a predetermined value. The cut valve is provided to prevent the fuel in the fuel tank from leaking to the outside through the fuel vapor pipe when the automobile turned or tilted. Namely, the cut valve has a float valve in its interior, and when the fuel level has risen, the float valve is adapted to rise to shut off a vent passage communicating with the fuel vapor pipe.
Japanese Patent No. 2972385 discloses a method of manufacturing such a fuel cutoff valve (hereafter referred to as the cut valve). In its embodiment, a cut valve is disclosed which is assembled such that a float having a projecting portion (valve element) capable of opening and closing a first through hole (valve seat), which allows a communicating passage open to the outside and the interior of the valve body to communicate with each other, is disposed in a substantially cylindrical valve body having the communicating passage and having one end closed and the other end open, and the other end side is closed by a cover member having a hole.
However, with the above-described conventional cut valve, if the vehicle makes a quick turn, tilts greatly, is rolled over, or travels on a road surface having large irregularity, the fuel in the fuel tank sways greatly, so that the float is unable to follow the swaying motion of the fuel, making it impossible to completely prevent the leakage of fuel to the vapor pipe side through the vent passage.